/*********
  Rui Santos
  Complete project details at https://randomnerdtutorials.com  
*********/

// Load Wi-Fi library
#include <WiFi.h>
#include <WebServer.h>

// Replace with your network credentials
// SSID & Password
const char* ssid = "ESP32WiFiAP";  // Enter your SSID here
const char* password = "123456";  //Enter your Password here
// IP Address details
IPAddress local_ip(192, 168, 1, 1);
IPAddress gateway(192, 168, 1, 1);
IPAddress subnet(255, 255, 255, 0);
// Set web server port number to 80
WiFiServer server(80);

// Variable to store the HTTP request
String header;

// Auxiliar variables to store the current output state
String output26State = "off";
String output27State = "off";

// Assign output variables to GPIO pins
const int output26 = 26;
const int output27 = 27;

// Current time
unsigned long currentTime = millis();
// Previous time
unsigned long previousTime = 0; 
// Define timeout time in milliseconds (example: 2000ms = 2s)
const long timeoutTime = 2000;

void setup() {
	Serial.begin(115200);
	// Initialize the output variables as outputs
	pinMode(output26, OUTPUT);
	pinMode(output27, OUTPUT);
	// Set outputs to LOW
	digitalWrite(output26, LOW);
	digitalWrite(output27, LOW);

	WiFi.softAP(ssid, password);
	WiFi.softAPConfig(local_ip, gateway, subnet);
	Serial.print("Connect to My access point: ");
	Serial.println(ssid);
	server.begin();
	Serial.println("HTTP server started");
	delay(1000);
	// Print local IP address and start web server
	Serial.println("");
	Serial.println("WiFi connected.");
	Serial.println("IP address: ");
	Serial.println(WiFi.localIP());
	server.begin();
}

void loop(){
  WiFiClient client = server.available();   // Listen for incoming clients

  if (client) {                             // If a new client connects,
	currentTime = millis();
	previousTime = currentTime;
	Serial.println("New Client.");          // print a message out in the serial port
	String currentLine = "";                // make a String to hold incoming data from the client
    while (client.connected() && currentTime - previousTime <= timeoutTime) {  // loop while the client's connected
      currentTime = millis();
      if (client.available()) {             // if there's bytes to read from the client,
        char c = client.read();             // read a byte, then
        Serial.write(c);                    // print it out the serial monitor
        header += c;
        if (c == '\n') {                    // if the byte is a newline character
			// if the current line is blank, you got two newline characters in a row.
			// that's the end of the client HTTP request, so send a response:
			if (currentLine.length() == 0) {
			// HTTP headers always start with a response code (e.g. HTTP/1.1 200 OK)
			// and a content-type so the client knows what's coming, then a blank line:
			client.println("HTTP/1.1 200 OK");
			client.println("Content-type:text/html");
			client.println("Connection: close");
			client.println();
            
            // turns the GPIOs on and off
            if (header.indexOf("GET /26/on") >= 0) {
				Serial.println("GPIO 26 on");
				output26State = "on";
				digitalWrite(output26, HIGH);
            } else if (header.indexOf("GET /26/off") >= 0) {
				Serial.println("GPIO 26 off");
				output26State = "off";
				digitalWrite(output26, LOW);
            } else if (header.indexOf("GET /27/on") >= 0) {
				Serial.println("GPIO 27 on");
				output27State = "on";
				digitalWrite(output27, HIGH);
            } else if (header.indexOf("GET /27/off") >= 0) {
				Serial.println("GPIO 27 off");
				output27State = "off";
				digitalWrite(output27, LOW);
            }
            
            // Display the HTML web page
            client.println("<!DOCTYPE html><html>");
            client.println("<head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">");
            client.println("<link rel=\"icon\" href=\"data:,\">");
            // CSS to style the on/off buttons 
            // Feel free to change the background-color and font-size attributes to fit your preferences
            client.println("<style>html { font-family: Helvetica; display: inline-block; margin: 0px auto; text-align: center;}");
            client.println(".button { background-color: #4CAF50; border: none; color: white; padding: 16px 40px;");
            client.println("text-decoration: none; font-size: 30px; margin: 2px; cursor: pointer;}");
            client.println(".button2 {background-color: #555555;}</style></head>");
            
            // Web Page Heading
            client.println("<body><h1>ESP32 Web Server</h1>");
            
            // Display current state, and ON/OFF buttons for GPIO 26  
            client.println("<p>GPIO 26 - State " + output26State + "</p>");
            // If the output26State is off, it displays the ON button       
            if (output26State=="off") {
				client.println("<p><a href=\"/26/on\"><button class=\"button\">ON</button></a></p>");
            } else {
				client.println("<p><a href=\"/26/off\"><button class=\"button button2\">OFF</button></a></p>");
            } 
               
            // Display current state, and ON/OFF buttons for GPIO 27  
            client.println("<p>GPIO 27 - State " + output27State + "</p>");
            // If the output27State is off, it displays the ON button       
            if (output27State=="off") {
				client.println("<p><a href=\"/27/on\"><button class=\"button\">ON</button></a></p>");
            } else {
				client.println("<p><a href=\"/27/off\"><button class=\"button button2\">OFF</button></a></p>");
            }
            client.println("</body></html>");
            
            // The HTTP response ends with another blank line
            client.println();
            // Break out of the while loop
            break;
          } else { // if you got a newline, then clear currentLine
			currentLine = "";
          }
        } else if (c != '\r') {  // if you got anything else but a carriage return character,
			currentLine += c;      // add it to the end of the currentLine
        }
      }
    }
    // Clear the header variable
    header = "";
    // Close the connection
    client.stop();
    Serial.println("Client disconnected.");
    Serial.println("");
  }
}